Plastic gift cards (resembling credit cards) have become very popular with most major retailers in recent years and now that most of the fast food industry has (most only fairly recently) begun to accept credit cards they, too, are taking advantage of their magnetic stripe capabilities.
So far I've discovered these 'convenience cards' at Jack in the Box (Jack CA$H), McDonald's (Arch Card), Burger King, Taco Bueno, Sonic Drive-In, White Castle, and Starbucks. Some of the chains even have special websites for their cards and use the new web addresses in their TV ads, like www.mytacobuenocard.com and www.mysoniccard.com.
The industry seems to have a lot of confidence in the brand loyalty-building abilities of these cards. McDonald's, for example, is putting 13 million $1 cards out there for free via Southwest Airlines and American Express.